Probably wise to find out where water comes from & where it goes before buying property these days, it's a pretty big issue & pretty regulated. Water over the dam now I know, but a learning experience.
The septic likely will need to be fixed - as in, a whole new one put in. I'm not sure I'd want to live dumping my raw septic on some one else's property.....
We are not lawyers, so our advise on whether to do it yourself or sue the former owner/ real estate people depends on your local laws & who said what about what. Most states have disclosure laws, but you don't seem to want to mention too much about this, so it's hard to offer even casual advise. You need real local legal advise in any case....
As to the feuding - I don't think there is a neighborhood without one.

Try to keep yourself out of the old arguments as others say - you have plenty of time to start your own new ones.
Good luck. Sounds like a nice place, with a few little bugs to work out.
--->Paul